Tories



March 1 1927. 1,619,161

7 H. STEVENSON ELECTROMAGNETIC sounn RFPRODUCER Filed July '16, 1926 5 Sheets-Sheetl 1 & 111111111111? 1 IN V EN TOR.

1E.;E w Images woo W,

ATTORNEY March 1 1927.

H. STEVENSON ELECTROMAGNETIC SOUND REPRODUCER Filed July 16, 1925 3 Sheets-Sheet 2 INVEVTOR.

March 1 1921. 1,619,161

H. STEVENSON- ELECTROMAGNETIC SOUND REPRODUCE'R Filed July 16. 1926 5 Sheets-Sheet 3 Patented Mar. 1, 1927.

UNITED STATES PATENT OFFICE.

HARRY STEVENSON, F KEARNY, NEW JERSEY, ASSIGNOR TO BRANDES LABORA- TORIES, INCL, OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ELECTROMAGNETIC SOUND REPRODUGER.

Application filed July 16, 1926. Serial No. 122,853.

My ,invention relates broadly to electromagnetic sound reproduoers and more particularly to asound reproducer employing a conical shaped sound reproducing diaphragm for the reproduction of musical notes over the entire range of frequencies encountered in radio broadcast reception.

My invention relates to that class of cone speakers which depend for their operating characteristics upon a sound amplifying cabinet in which the cone diaphragm is housed, as shown more particularly in copending application for Letters Patent, Ser. No. 60,128, filed October 2, 1925 by Cyril A. Brigham and David H. Moss.

One of the objects of my invention is to provide a simplified construction of cone speaker capable of manufacture and production inexpensively on a large scale.

Still another object of my invention is to provide a cone speaker having its parts arranged in such manner that shipment and assembly of the loud speaker may be facilirated and adjustment secured without the employment of expert or skilled labor.

Another object of my invention is to provide a cone speaker having a sound reproduc ing diaphragm which is supported directly from its apex through the mounting which 0 carries the electron'iagn-etic driving mechanism whereby the complete electromagnetic operating mechanism may be mounted upon the base which carries the sound amplifying cabinet,

A still further object of my invention is to provide an electromagnetic operating mechanism for a cone speaker wherein adjustment may be made between the electromagnets and the driving arn'iature for the reproduction of sound at maximum tone quantity for different signal characteristics.

Still another object of my invent-ion is to provide a cone speaker in which a single casting is provided for forming the sole means of supportfor the conical sound reproducing diaphragm and an electromagnetic driver which adjustably positioned in the upper extremity of the casting.

A still further object of. my invention is to provide a construction of electromagnetic driver for sound. reproducers wherein adj ustment may be made of an electromagnetic operating structure with respect to a driving armature by movement of the electromagnetic structure through variable planes parallel to the driving armature for the selection of a desired magnetic gap between the electromagnets and the driving armature for the reproduction of sound of a particular characteristic at maximum etficiency.

Still another object of my invention is to provide a construction of electromagnetic sound reproducer where the electromagnetic operating mechanism is provided with a three point suspension with respect to the driving armature for insuring accurate adjustment of the electromagnetic operating mechanism with respect to the driving armature.

My invention will be more clearly understood by reference to the following specification and the accompanying drawings in which:

Figure 1 is a cross-sectional view taken through the loud speaker of my invention showing the support for the electromagnetic operating mechanism partially in side elevation; Fig. 2 is a view through the loud speaker construction of Fig. 1 looking in the direction of line 22; Fig. 3 is an enlarged view of the electromagnetic sound operating mechanism illustrating the 3 point suspension construction in more detail; Fig. 4 is a fragmentary plan view of the electromagnetic operating mechanism showing the arrangement of the parts thereof; F1g. 5 1s a view looking in the dlrection of the driving armature member within the electromagnetic operating mechanism of the cone speaker; and Fig. 6 illustrates the parts which form the control system for regulating the movement of the electromagnetic operating mechanism and controlling the adjustment thereof.

In the manufacture and distribution of cone speakers constructed in accordance with the copending application above referred to, difliculty has been experienced in the assembly of the apparatus by reason of the dual mounting of the conical sound reproducing diaphragm and the electromagnetic operating mechanism. This has required the accurate spacing of the sound reproducing diaphragm support from the support for the electromagnetic driver and the construction has been so fragile that a large percentage of rejections and apparatus returned for repair has resulted. The construction of the cone speaker as set forth herein is the result of research and development after a study upon a single casting.

ducer are mounted.

of the operation of thousands of cone speakers manufactured in accordance with said aforementioned application in actual service. I provide aconstruction of electromagnetic operating mechanism and sound reproducing diaphragm which may be readily assembled within the sound amplifying cabinet with the electromagnetic driving. mechanism ant. the sound reproducing diaphragm mounted This construction facilitates manufacture, for the complete electromagnetic mechanism and sound reproducing diaphragm may be manufactured and-assembled in one place and then mounted within the sound amplifying cabinets in still a difierent place, permitting the utilizatron of manufacturing facilities to the greatest advantage. The adjustment which ll provide permits the accurate movement of the electromagnetic driving mechanism with re- .spect to the armature for the selection of a magnetic gap of proper size for efficient reproduction of sound of a par 'cular characteristic. The details of the construction of the electromagnetic sound reproducer of my invention will be better understood by dct-ail reference to the drawings wherein reference character 1 designates a base member from which the parts of the sound repro- A cabinet structure 2 entirely encloses the sound reproducing diaphragm and electromagnetic operating mechanism, A vertically extending castingB is positioned within the cabinet structure and rests on feet at, 5, and 6 on the lower portion of the casting through which bolt members 7 pass for anchoring the vertically extending casting 8 firmly to the base. The cast- .ing 3 terminates in a circular head portion 8 which is centrally apertured as represented at 9 and counterbored and screw threaded as represented at 10. The apertured portion 9 forms an annular abutment face represented at 11 against which an armature member 12 is arranged to be seated and secured in position by lock ring- 14 operating in the screw threads 10. The armature construction which I prefer to employ is set forth more particularly in Letters Patent 1,588,545 granted to lVilliam H. Gerns, June 15., 1926. The armature member may be mounted between gaskets in the manner set forth in Patent No. 1,526,626 granted to Cecil E. Brighan, February 17, 1925. The

. h armature member 12 delivers sound vibra tions through a link member 15 to the apex of an elliptical conical shaped sound reproducing diaphragm 16. Connection is made between the link member 15 and the apex of the conical shaped sound reproducing diaphragm by means of members 17 and 1S contacting with opposite surfaces of the sound reproducing diaphragm and secured together a unit for gripping the apex of the sound reproducing diaphragm by means apparatus when muuu'l'actured on a ti j production scale. I provide a pair of extensions :20 and 2t integral with the circular portion tl oi the vertically extending casting l and on these ei-itensions l: secure. a pair of 'Jupportuembcrs and 2?) which terminate at diametrically opposite points or" an elliptical shaped rini ii'ienrbcr The members 732 and 21'} are secured. to the elliptical rim member 52-1: along;- the lcngn't diameter of the rim member as represented at 2:") and 22th so that the elliptical rim member ii has its lunch tudi al axis extending in a plane coincidentwith the plane of the vcrticzillv extending The outer periphem of the elcasting o. I liptical shaped conical diapl'u'iurm u; ilouts within the elliptical shaped rim Bl through a connection with flexible material 11TH.- cured by a framing rim Ell coinciding with the rim ill and secured at a plurality of points about its peripherv by imam of the screw devices or other suitable means as rep resented at 29 l provide another set of hm memlu's which are cast integral with the vertically extending castingll reprowuted at 30 ill and 5352. l hcse luu' members ex tend from the side of the circular portion 8 and are loiuritudinally apr-rtured to lidablv receive pin members 33. ill and 35 carried by the plate St; on which the electromagnetic o 'ieratingr mechanism is mounted. The vice tromap neticoperating-r mechanism includes elcctromagnets 3'? and permanrnl magnetic cm 38. The electrianuuruetiv svstem is provided with laminated pole plot-oz; rcpresented. at ill) for reduction in iron losses and securing of maximum eliicicncy. i k nonnuu 'netic plate member all) is secured across the poles of the permanent magnetic system 38 and to this plate member there is riveted a screw device ll. The screw device ll may be advanced or retracted in. a screw threaded member l-Ll which is jourrmlcd within the brat which spans the entire loo llo

a substantial mounting. I provide a retaining member 49 with a set screw therein for cone shaped enabling a tubular member 51 having an internal cone shaped bore to be frictionally gripped thereover and secured in position by means of the screw member 52. The tubular member 51 may thereby be readily applied or secured in position over the extension from the outside of the cabinet when the apparatus is assembled. An operating knob 53 is next positioned by means of a set screw upon the extension rod 51 and the position of the electromagnetic operating mechanism with respect to the driving armature controlled by a sliding movement of the suspension pins 34 and 35 in the cylindrical bores of the lug members 30,31 and 32 on the cylindrical housing 8.

It will be observed that all of the parts oftheelectromagnetic sound reproducer are mounted from the central vertically extending casting. 3 and that for this purpose a plurality of lugs are provided extending in opposite directions and in different planes from the cylindrical portion 8 of the main casting. The ring member 14 by which the armature 12 is secured in position may be slotted at different points about its periphery for permitting a tool to grip and rotate the rim. A spring device 54 is disposed between the adjustable plate member 36 and the ring member it for preventing vib 'ation of the parts under continued action of the electromagnetic operating mechanism. The terminals for the electromagnetic system are represented at and a flexible conductor 56 leads from the terminals to the exterior of the cabinet for permitting connection to be made with the output. circuit of an amplification system.

The action of the screw device 42 is to secure micrometer i'i'iovement of the member 40 by reason of differential action oi the screw 41 which is ad *anced or retracted in the internal screw threads of the device 42 in accordance with the movement of the control knob 53 from the exterior of the sound amplifying cabinet structure. By reason of the micrometer adjustment extremelv accurate magnetic gap clearances may he s cured.

I have found the construction of: cone speaker illustrated in the drawings to be extremely practical for manufacture and production processes and eflicient in its electrical operation, and although I have illustrated one of its preferred embodiments I desire that it be understood that modifications may be made and that no limitations upon the invention are intended other than are imposed by the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of the United States is as follows: i

1. An electromagnetic sound reproducer comprising a vertically extending casting, an electromagnetic driving mechanism supported by said casting, a plurality of lug members integrally related to the exterior of said casting, an electromagnetic operating mechanism, a frame concentrically arranged within said casting for carrying said electromagnetic operating mechanism, and a plurality of pins extending between said frame and the lug members on said casting whereby said electromagnetic operating mechanism may be slidably adjusted within said casting, a driving armature actuated by said electromagnetic operating mechanism, and a cone shaped sound reproducing diaphragm having its apex connected with said armature whereby mechanical vibrations of said armature impart similar movement to said diaphragm.

2. An electromagnetic sound reproducer comprising a base member, asound amplifying cabinet carried by said base member, a vertically extending casting secured to said base member within said sound amplifying cabinet, an electromagnetic operating mechanism carried by said vertically extending casting, an armature member positioned in said casting. a cone shaped diaphragm and aconnection between said armature member and said cone shaped diaphragm, an electromagnetic operating mechanism slidably positioned in said casting and means controllable from the exterior of said cabinet for adjusting the position of said electromagnetic operating mechanism with respect to said armature for securing maximum eli iciency in the reproduction of sound by said cone shaped diaphragm.

3. An electromagnetic sound reproducer comprising a base, a sound amplifying cabinet mounted upon said base, a casting carried by said base within said sound amplify ing cabinet, a cone shaped diaphragm, said casting providing a housing for an electromagnetic driving mechanism including an armature arranged to impart mechanical vibrations to said cone shaped diaphragm. an electromagnetic operating mechanism for actuating said armature, and means controllable from the exterior of said sound amplitying cabinet for adjusting the spacial relation of said electromagnetic operating 1nechanism and said driving armature for the reproduction of sound at maximum efiiciency.

4. An electromagnetic sound reproducer comprising a base, a sound amplifying cabinet mounted on said base, a vertically extending casting carried by said base interiorly of said amplifying cabinet, said cabinet tern'iinatino' in a circular head portion torming a housing for an electromagnetic sound reproducing mechanism, a plurality of lug members extending from said circular housing, a cone shaped sound reproducing dia phragm positioned within said cabinet, a

driving armature [)OSltlO-ll-Qtl within said circular housing and connected with the apex of said cone shaped sound reproducing; diaphragm, an electromagnetic operating mechanism slidably positioned within said circular housing, a. rotatable control knob )OSitio'ned exte'riorly oi said sound amplitying CtllIdHGi, and a screw connection within said sound a n'iphiym g cabinet between said control knob and said electromagnetic operating mechanism for imparting translator-y motion into corresponding cylindrical bores in said circular head, and a guide secured to said circular head for advancing or retracting said electromagnetic operating mechanism within said circular head with respect to said driving armature, said pins sliding within said cylindrical bores for aligning said electromagnetic operating mechanism with said drivin armature.

6. An electromagnetic sound reproducer comprising a base member, a vertically extending standard on said base member, a

housing for an electromagnetic driving mechanism positioned on said standard, a plurality of lug members contiguous with said housing and extending in opposite directions therefrom, col'mections between a pair of said lug members on one side of said housing; and said frame, a conical shaped diaphragm, a driving armature positioned within said housing and connected with the apex of said conical diaphragnn'a plate member carrying an electromagnetic operating mechanism arranged to be projected into said housing and variably aligned with said driving armature, a plurality o't pin members carried by said plate, said pin members arranged to project into a corresponding number of lugs on the opposite side of said housing, and a screw device for advancing or retracting said pin members within said last member lugs for lining the size of said magnetic gap between said electromagnetic o1 erating mechanism and said driving armature.

7. An electromagnetic sound rcm'oducer comprising a base, a. member extending from said base and terminating in a housing tor an electromagnetic sound l'(.l)l'()(l1l(6l', a sound reproducing diaphragm, a driving armature located in said housing and arranged to impart mechanical 'ihrations to said diaphragm, a bridge member l-onnectcd across said housing and elcctronmgnctic operating mechanism, a frame carrying said electromagnetic operating mechanism, a plurality of pins secured to said frame and arranged to be projected through bores formed in said housing, and a screw mechanism carried by said bridge member whereby said frame may be advanced or rctrzwted for adjusting the distance between said electromagnetic operating" mechanism and said driving armature.

8. In an electromagnetic sound rcpro- (lucer the combination of an elcctrolnognctic driving mechanism inchuling a driving armature member, a conical shaped sound reproducing diaphragm. a rod member extending from said driving armature member through the apex o 1 said conical shaped sound reproducing diaphragm, and a. spring collet chucl: device carried by the apex oi said conical shaped reproducing diaphragm tor gripping said rod member at a selected point alongthe length thereof.

9, An electromagnetic sound reproduccr comprising a supporting member, a housing for an electromagnetic driving mechanism carried by said supporting member, a conical shaped sound reproducing diaphramn, a, driving armature located within said housing and arranged to impart mechanical vibrations to the apex of? said conical shaped sound reproducing diaphragm, an electromagnetic operating): mechanism slidably positioned within said housing, a bracket member extending from one side of said housing, a screw device join-lulled in said bracket member. and means for rotating said screw device 'lor imparting trauslatorv movement to said electromannetic operating mechanism whereby the distance between said electromagnctic operating mechanism and said arn'iatm'c member may be varied.

10. In a loud spcal rcr construction a sound amiilii yinp' chamber. an GlCt'll(')ll'litQl1Cll(2 operating mechanism and sound rcprodlu-cr positioned within said sound amplifying chamber, said electronian'netic olicrating mechanism having a rotatable adjusting device extending therefrom to a. position adjacent the wall of said sound amplifying Hill chamber, an extension device arranged to be passed through the Wall of said sound amplifying chamber and secured to said rotatable adjusting device and a control knob secured upon said extension device exterior of the Wall of said sound amplifying chamber for adjusting said electromagnetic operating mechanism from the exterior of said sound amplifying chamber.

11. In a sound reproducing apparatus a sound amplifying chamber, an electromagnetic operating mechanism and sound reproducing diaphragm Within said chamber, a rotatable device on said electromagnetic operating mechanism for adjusting said mechanism, said rotatable device terminating adjacent the interior Wall of said sound amplifying chamber and a tubular member insert-able through the Wall of said sound amplifying chamber from the exterior of said chamber for gripping said rotatable device and a control knob arranged to be secured on said tubular member exterior of said chamber for adjusting said electromagnetic operating mechanism.

In testimony whereof I allix my signature.

HARRY STEVENSON. 

